Addition of a particulated electrically conductive material such as graphite or metal flakes, metal coated glass spheres, and the like to a conductive carbon ink as disclosed in the cross-referenced patent application filed concurrently herewith provides a desirable increase in electrical conductivity to improve the operational reliability of a flash lamp array circuit pattern using this type ink. More particularly, such additives reduce the incidence of lamp failures to flash by a considerable degree while further enabling the modified inks to serve as integral fuse elements in the circuit pattern. On the other hand, there still exists a need to further improve the reliability of fuse operation beyond that already obtained since increasingly lower intensity flash lamps are now being used which creates a greater likelihood of a short circuit condition being experienced. It is a primary object of the present invention, therefore, to provide a modified carbon ink demonstrating still greater operational reliability when used as integral fuse elements in the circuit pattern. Another important object is to provide a modified carbon ink exhibiting improved electrical resistance and dielectric breakdown voltage characteristics after thermal decomposition when serving as the fuse means in a flash lamp array circuit. Such operative characteristics for the fuse means in this type circuit helps prevent application of a successive high voltage firing pulse to an already flashed lamp.